As magnetoresistance effect elements, a giant magnetoresistance (GMR) element formed by a multi-layered film with a ferromagnetic layer and a nonmagnetic layer and a tunnel magnetoresistance (TMR) element using an insulating layer (a tunnel barrier layer or a barrier layer) as a nonmagnetic layer are known. Generally, a TMR element has higher element resistance than a GMR element and has a magnetoresistance (MR) ratio higher than a GMR element. A TMR element has attracted attention as an element for a magnetic sensor, a high-frequency component, a magnetic head, and a nonvolatile RAM (MRAM).
As writing systems of an MRAM, a system performing writing (magnetization reversal) using a magnetic field generated by a current and a system performing writing (magnetization reversal) using a spin transfer torque (STT) generated by causing a current to flow in a lamination direction of a magnetoresistance element are known.
In the system using a magnetic field, there are cases in which, when the size of the element is decreased, there is a limit on a current that can flow through a thin wiring, and appropriate writing may not be able to be performed.
In contrast to this, in the system using a spin transfer torque (STT), ferromagnetic layers (a fixed layer and a reference layer) of one side perform spin polarization of a current, spin-polarized spin is transferred to ferromagnetic layers of the other side (a free layer and a recording layer) using a current, and writing (magnetization reversal) is performed using a torque (STT) generated at that time. For this reason, the system using a spin transfer torque (STT) has an advantage that a current required for writing decreases as the element size decreases.